Category Archives: Interactions

Simon says "Come up with a better idea"

Making Enemies III

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The final fundamental question that needs to be answered when designing enemies for an action game is:

3.  How will the enemy overreact and expose their fatal weakness?

Every enemy needs a flaw, a chink in their armor that can be exploited by the player. A massive enemy with an equally massive health bar that virtually ignores you as you whittle away isn’t very satisfying. Their defeat is too gradual; the moment of their defeat nearly imperceptible. The true glory of victory isn’t the explosion or the death rattle, it’s before that, when the outcome is guaranteed, but not yet realized. That requires a fatal flaw.

  • A melee charge that travels a bit too far, letting the player get behind them
  • Running out of ammo at just the wrong time, leaving them defenseless at a crucial moment
  • Losing their temper and leaving cover, giving up their advantageous position
  • Realizing a second too late they are standing next to an explosive barrel

The issue for game designers is not the flaw, but calling the player’s attention to it. Shooting at the glowy bits is a common trope. It works precisely because it is a cliche, but it’s about as elegant as putting up a sign that says “Shoot here, dummy.” And not as effective, either. Using Water spells on Fire enemies makes more sense, but is about as exciting as turning a key in a lock. It’s easy to see why so many games have resorted to flashing random button sequences as a facsimile of exploiting a weakness, at least screen-filling UI prompts are hard to miss.

Simon says "Come up with a better idea"

The ultimate warrior

The problem is that there shouldn’t be a problem. Nature’s molded us into natural born killers.  We know when an enemy is vulnerable — from injury or inattention or separation from the herd — we can spot the target of opportunity if we see it. But there is so much going on in an action game, so much happening at such a relentless pace, it can be hard to filter out what is important. That’s why the best flaws are revealed when an enemy reacts to the player, or more accurately when they overreact.

The moment of reaction is ideal because the player is paying attention. Their action caused the reaction.  Everyone over-emphasizes the results of their own activity and focuses on the effects that they cause. They want to watch the ripples from the stones they are throwing. So they will be watching closely and are more likely to notice their opportunity. Also, since the player is the cause of the reaction, they will naturally experiment with it and understand the connection much faster. We are natural scientists, even children employ the scientific method, so giving the player control over the weakness will make them more likely to discover it.

Making it an overreaction will make it more obvious. It can be exaggerated and call attention to itself by being slightly inappropriate. It will also give the player the satisfaction of having outsmarted an enemy. It’s one thing to exploit a weakness they cannot control, but it’s so much better to capitalize on a mistake they shouldn’t have made. Provoking an enemy into a fatal error is one of the most satisfying experiences a game can provide, and the more cunning an enemy seems, the more delightful it is to fool them.

My technique is no technique

Making Enemies II

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The second fundamental question crucial to designing enemies for an action game is:

2.  How will this enemy counter the player’s first-tier tactics?

Action games give the player a hammer.  It looks like a broadsword or an assault rifle, but it’s still a hammer.  And when you have a hammer, every enemy looks like a nail.  A nail doesn’t have to do anything complicated to look smart; all it has to do is avoid getting hammered right away!  If an enemy forces the player to reach into their toolbox for a second option, they’ll show that they are clever, and the player will feel clever, too.

My technique is no technique

Good AI

The obvious way to counter the player’s basic tactics is through simple invulnerability.  “That armor is too strong for blasters.”  It’s crucial that this invulnerability is communicated clearly, through the look of the enemy, how they respond to the player’s attack, and any supporting effects or dialog.  If the player doesn’t realize they are not being effective — or is misled into thinking they have done damage when they haven’t — the enemy will just seem poorly tuned.

  • Carries a shield that blocks bullets, but any other kind of attack causes them to drop their shield and expose themselves to fire
  • Cannot be killed with melee attacks and must be thrown into an environmental hazard
  • Bullets bounce off the vehicle, but you can snipe the driver out

A more subtle way to foil the player’s main method of attacking is to preemptively take action to prevent it or require another action be taken before the attack to make it a two-step process.  These enemies appear intelligent, but they still allow the player to user their (hopefully) satisfying primary attack.

  • Takes cover behind an object, requiring the player to flank or drive them out of cover
  • Wears a full-body energy shield that must be taken down before they can be damaged by normal bullets
  • Blocks every sword swing, but is stunned if their own swing is blocked

It is also possible for an enemy to behave in such a way that it is more difficult for the player to execute on their first-tier attack.  This can be difficult to tune for multiple difficulty levels, but if the counter-strategy only works on the their main attack, then players of any skill level should be able to cope by changing their tactical choices instead of having to execute beyond their skill level.

  • Flees out of melee range faster than the player can pursue, but has no defense against ranged attacks
  • Keeps up a constant barrage of fire, forcing the player to hide, but unable to get away from a grenade thrown from behind cover

Again, the idea is not to make an enemy that is difficult or frustrating, or even especially sophisticated, but that has a clear counter for the player’s primary attack.  This will require the player to stretch, tactically, and figure out their alternatives, but any amount of experimentation should be rewarded by a quick victory.

Making Enemies

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There are three fundamental questions at the heart of designing enemies for an action game.  The first is:

1.  How will this enemy force the player to react?

Any enemy can be tuned to be deadly.  In fact, overly lethal enemies are often a symptom of a poorly balanced game; nobody enjoys being flattened by an unstoppable steamroller.  And any enemy can be crippled until it is merely a target in a shooting gallery.  When a designer has run out of ideas for making an enemy fun, the fallback position is usually “bullet sponge”.  The key to designing an enjoyable opponent for the player is finding a way to split the difference — forcing the player to react to an enemy without resorting to killing them.

To achieve this, it is important for the enemies to take the initiative and make the first move.  Players will tend to repeat the same tactics over and over if they continue to work.  By preempting their default strategy the enemy will challenge them to improvise, to think more strategically, or to experiment with new tactics.

  • Disarm the player, or prevent them from using their primary attack
  • Invade the player’s space, requiring them to start a fight before they are ready
  • Use a special non-lethal attack that stuns or knocks the player around, preventing them from fighting back until they can counter it

Another good way to force the player to react beyond taking and dealing damage, especially in shooters, is to force them to move.  By making the player aware of their environment — the connectivity of the space and their physical relationship to their surroundings — a well-designed enemy can greatly increase the strategic depth of combat.

  • Attack from a range that is outside or inside the player’s optimal range
  • Deny the player use of an area (as with a long-fused grenade) forcing them to move to a different area
  • Take cover behind an object, requiring the player to switch positions and flank them
  • Charge to melee range, so the player must retreat or change weapons

Another way the player can be made to react is by changing something significant about the fight so they have to re-prioritize their targets or switch tactics.  This change doesn’t have to be immediately dangerous, it just needs to tilt the battlefield in a new direction.

  • Begin a devastating attack with a long wind-up that can be interrupted
  • Perform an attack that ends in a temporary vulnerability that the player will want to exploit
  • Allow the player’s current target to quickly withdraw or become invulnerable, removing themselves from the fight temporarily

Another tool for causing a reaction that is often overlooked is dialog or dramatic behaviors that don’t serve a combat function, but can still influence the player and cause a reaction.

  • Taunt or mock the player to incite anger
  • Announce an upcoming action (like reloading) to draw the player’s attention
  • Threaten or attack one of the player’s allies, giving them a chance to be a hero

Far from being a secondary concern to be considered after an enemy can already fight well, these non-lethal interactions with the player should be designed first and receive the most attention.  Once the player is engaging an enemy with their mind — and not just their fingers and their weapons — they will be having fun.  At that point it is easy to make them more or less lethal as the balance requires.

Definition: Verisimilitude

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Verisimilitude

The quality of seeming to be true, of resembling reality

Why is Wii Bowling like a Hemingway novel? (Beside the fact that they are each made better by adding alcohol.) They both benefit from the effects of verisimilitude. Authentic characters and believable dialog enhance the reader’s engagement in a story; they do not call attention to the fact that they are fictitious by violating our expectations about what might really happen. In the same way, the way the player’s movement in Wii Bowling matches the form and timing of real bowling avoids the awkward break with reality many people feel when playing video games.

Verisimilitude is important for many aspects of game design. Poorly tuned physics systems, bone-headed AI behaviors, inaccurate collision tests, unrealistic lighting, and scores of other common problems all result in a game feeling “off” or “fake”. That is why players can complain about an “unrealistic” space marine pulse rifle; even though no such thing actually exists, they have an intuition of what it would be like if it did exist.

Teach me!

Exactly like this...

However, nowhere is a lack of verisimilitude felt more strongly than in poorly designed controls. If an in-game action clashes with the input method to which it is mapped, it will always break the player’s flow and they will never be comfortable with the controls. Ideally, when the player is engaged with a game, the controller fades into the background and they are no longer aware of it, but an awkward or discordant control scheme is a constant reminder that they are playing a game. Here are some guidelines to avoid mismatched mappings:

  • The duration of an input should match the duration of the action. If a single button press is mapped to a melee attack, the animation for the attack needs to be short and responsive, just like the button press. If the animation needs to be longer, it should require several presses, or a press and hold, that takes roughly the same amount of time for the player to execute. Rapidly tapping a button during a grapple is a bit cliché, but it works because it extends the duration of the input to match the onscreen action.
  • Do not map discrete actions to analog inputs. A game where the player initiates a melee attack with the throw on a thumbstick is using an analog input (the range of motion of the thumbstick) to trigger a discrete action (punching a Triad thug in the face) which makes the player feel detached and removed from the action. This is often described as “soft” or “unresponsive”.
  • Do not map unrelated actions to integrated inputs. The D-Pad is not a set of four buttons, no matter how many games treat it as such. It physically represents four cardinal directions, and it is virtually impossible for a player to get comfortable with treating them separately. In the same way, a thumbstick is not a an arbitrary number of discrete buttons arrayed in a circle, and using them that way will prevent most players from engaging completely.
  • Do not use two-step inputs for single-step actions. The easiest way to add inputs to the controller is to use chords, two buttons pressed at the same time. This works great for “zoom” and then “shoot” because it is a two-step action, but is jarring when used for actions that appear to happen all at once.
  • If an action cannot be mapped to the controller, it should be cut. This is the hardest rule, but the most important. Some actions conflict with one another on a fundamental level, and though it may be tempting to cram them both on the controller, the game will suffer for it. It’s better to have a single action that players can execute confidently and competently than multiple actions that are confusing and cluttered.